I've always preferred the upper deck on KE, and choose a window either in front of or at the exit row. The window has the mini-locker at your side which is very nice for storage and for as a side table. The seats are like pods, so it doesn't matter how much you recline or the person in front/back of you reclines, you won't be contorting around them and vv.

Overall, I think KE's J is a good product for the value.